1. Field of the Invention
The present invention relates to apparatus for and methods of personal identification. It has particular utility in relation to apparatuses which are required to capture an image of anterior features of an eye and display an image to the eye simultaneously. Such an apparatus might be used in an authentication device which captures an image of an iris of a user.
2. Related Art
Apparatuses for capturing an image of a persons' eye at the same time as providing a display for viewing by the person's eye are known. For example, IriScan Inc. market a System 2000EAC.TM. authentication apparatus. Another example is the pupillometer apparatus disclosed in international patent application WO 92/05736.
The former apparatus comprises an iris pattern capture unit and an identification code generation unit. The iris pattern capture unit has a housing having two apertures. An infra-red illumination source is arranged to project visible and infra-red light through the first aperture to illuminate a person's eye. A camera, installed within the apparatus is arranged such that its field of view is through the second aperture. In using the apparatus the person looks through the second aperture at a display which reproduces the image seen by the camera. At the same time, light from the illumination source is reflected from the person's eye through the second aperture towards the camera. The display enables the person to position his eye such that it is in focus and located in the centre of the field of view of the camera.
In practice it is found that the user must position his or her eye within a narrow range of distances from the device in order for a successful capture of an image of the user's eye to be achieved.
A fovea-centred eye fundus scanner is disclosed in European Patent Application 0 126 549. Because the apparatus uses scanning optics to examine the fundus (retina and choroid) of an eye, it is complex and bulky.